This invention relates to an arrangement for measuring the level of oil pollution in water, and more particularly to an infrared light scattering measurement system.
In many situations, such as in the discharge of water ballast from an oil tanker, it is necessary to measure the level of oil pollution in flowing water. The oil, which is generally in the form of finely dispersed droplets, is often measured by directing light from a diffuse visible source through the water and measuring scattered light at an angle to the incident beam. Whilst this method is simple and reasonably effective, it suffers from the disadvantage that deposition of dirt on the detection system reduces the incident light and can cause false readings to be produced. Furthermore, it is difficult with conventional light sources to produce a light beam intense enough for the detector to respond to low oil levels. Such a detector also gives a false reading when suspended solids, e.g. rust particles, are present in the fluid stream.